PCX Format: adjust bits per pixel


I’m editing PCX graphics files from old MS-DOS games and I use the built-in gimp plugin for that to import/export.

I have some issues I can’t solve:

  • I need an uncompressed PCX file. It seems gimp compresses when exporting it but I’m not sure. Because the game won’t load the file. How to export an uncompressed PCX file in gimp?

Read further below, because there could be another reason it’s not working in the game

  • Gimp is outputting 24bpp I think but the game using the PCX file requires 4bpp I read somewhere. How can I change the bpp in gimp? I don’t find this option anywhere.

Please note I’m a beginner in either gimp and the PCX format!

Change the mode of your image to indexed (menu Image → Mode → Indexed) and set number of colors to 16. Note that the colors of your image may change to adjust for the limited number of colors if you do this on an existing image.

Can you explain how you know it are 16 colors for 4 bpp?
So how can I calculate the number of colors for a bpp value (here 4).

I applied it and it works!!!

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4 bits are used to store a color, that means there can be 2 to the fourth power (=16) colors.